Composition for oral cavity

ABSTRACT

An oral composition includes high stain removal efficiency relative to its abrasive ability. The oral composition contains fused silica and a dental abrasive. The oral composition has a high stain removal ability relative to the abrasive ability thereof. In other words, the ratio (stain removal ability/abrasive ability) of the oral composition is high. Accordingly, the use of the oral composition makes it possible to efficiently remove stains without damaging the teeth more than necessary.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application ofPCT/JP2010/068070 filed on Oct. 14, 2010, and claims priority to, andincorporates by reference, Japanese Patent Application No. 2009-237785filed on Oct. 14, 2009 and No. 2010-099954 filed on Apr. 23, 2010.

TECHNICAL FIELD

The present invention relates to an oral composition. More specifically,the present invention relates to an oral composition comprising fusedsilica and a dental abrasive.

BACKGROUND

Teeth discoloration results from deposition of chromogenic substancescalled stains on the teeth, and this causes a serious problem in termsof aesthetic appreciation. As a means to remove stains, a common methodis such that an oral composition such as a dentifrice compositioncontaining a dental abrasive is held in the mouth using a tool such as atoothbrush, and the teeth are brushed. Because stains are removed mainlyby abrasion, it is believed that a higher stain removal effect isachieved by the use of a dental abrasive having a higher abrasiveability. From this viewpoint, a harder dental abrasive would bepreferable for the removal of stains, because a harder dental abrasiveis considered to abrade the tooth surface with more physical strengthand provide a high stain removal effect.

However, when an oral composition containing a dental abrasive having ahigh abrasive ability is used, there is a risk that the teeth may beabraded more than necessary. When the tooth surface is abraded, thedentine may be exposed, which may cause hypersensitivity. Further,because the exposed dentine has poor resistance to acid, tooth decay maybe promoted. For example, alumina, i.e., a typical example of a harddental abrasive, has an excellent stain removal ability, but alsodamages the teeth by abrasion. Although various improvements have beenmade to prevent damage to the teeth, the problem has not yet beensolved. Today, oral compositions rarely contain alumina.

Therefore, there is a demand for the development of an oral compositionhaving a high stain removal ability while having an appropriate abrasiveability; specifically, an oral composition having a high stain removalability relative to its abrasive ability (i.e., the balance between theabrasive ability and the stain removal ability is good).

For example, Patent Literature 1 discloses that an oral compositioncomprising two types of silica having different abrasivities (silicawith high abrasivity and silica with low abrasivity) as dental abrasivesis useful to remove stains without damaging the teeth. However, thisoral composition also contains highly abrasive silica, and thus has notexactly eliminated the risk of damaging the teeth.

CITATION LIST Patent Literature

-   -   PTL 1: Japanese Unexamined Patent Publication No. 2004-238321    -   PTL 2: Japanese Unexamined Patent Publication No. 2009-1638    -   PTL 3: Japanese Unexamined Patent Publication No. S62-241541

SUMMARY

An object of the present invention is to provide an oral compositionwhose stain removal efficiency is high relative to its abrasive ability.

The present inventors unexpectedly found that an oral compositioncontaining fused silica has a high stain removal ability, even thoughits abrasive ability is not particularly high; i.e., the stain removalability is high relative to the abrasive ability. Further, the presentinventors found that when an oral composition contains fused silica anda dental abrasive, the stain removal ability is even higher relative tothe abrasive ability. The present inventors completed the presentinvention with further improvements based on the above findings.

Fused silica is a type of silica used in the field of semiconductors,and is mainly used as a filler and the like, for example, inthermosetting resin for semiconductor sealant (for example, see JapaneseUnexamined Patent Publication No. 2009-1638). However, an oralcomposition containing fused silica is not known. Further, because fusedsilica is produced by fusing silica powder at high temperatures, thedensity is high, and the hardness is very high. As described above, aharder dental abrasive has a higher abrasive ability, and such a dentalabrasive may abrade the teeth more than necessary. Therefore, it wascompletely unexpected that an oral composition containing fused silicahaving a very high hardness would have a high stain removal abilitydespite its not very high abrasive ability.

Specifically, the present invention encompasses oral compositionsrecited in the following items, for example.

Item 1.

-   An oral composition comprising fused silica and a dental abrasive.    Item 2-1.-   The oral composition according to Item 1, comprising 0.25 to 8.5% by    mass of the fused silica.    Item 2-2.-   The oral composition according to Item 1, comprising 0.5 to 8.5% by    mass of the fused silica.    Item 3-1.-   The oral composition according to any one of Items 1 to 2-2, wherein    the BET specific surface area of the fused silica is 10 (m²/g) or    less.    Item 3-2.-   The oral composition according to any one of Items 1 to 3-1, wherein    the BET specific surface area of the dental abrasive is 20 to 1,000    (m²/g).    Item 4-1.-   The oral composition according to any one of Items 1 to 3-2, wherein    the fused silica has an oil absorption of 20 (mL/100 g) or less.    Item 4-2.-   The oral composition according to any one of Items 1 to 4-1, wherein    the dental abrasive has an oil absorption of 20 to 400 (mL/100 g).    Item 5.-   The oral composition according to any one of Items 1 to 4, wherein    the dental abrasive is at least one member selected from the group    consisting of precipitated silica, silica gel, fumed silica,    zircono-silicate, aluminum silicate, calcium phosphate, anhydrous    dicalcium phosphate, dicalcium phosphate dihydrate, tricalcium    phosphate, anhydrous calcium hydrogen phosphate, calcium hydrogen    phosphate dihydrate, calcium pyrophosphate, calcium carbonate,    calcium sulfate, aluminum hydroxide, water-insoluble sodium    metaphosphate, trimagnesium phosphate, magnesium carbonate, titanium    oxide, polymethylmethacrylate, bentonite, hydroxyapatite,    crystalline cellulose, polyethylene beads, and polypropylene beads.    Item 6.-   The oral composition according to Item 5, wherein the dental    abrasive is precipitated silica.    Item 7.-   The oral composition according to Item 6, comprising 5 to 26% by    mass, preferably 7.5 to 26% by mass, of the precipitated silica.    Item 8.-   The oral composition according to Item 6 or 7, comprising a total of    10 to 34.5% by mass of the fused silica and the precipitated silica.    Item 9.-   The oral composition according to any one of Items 6 to 8, wherein    the mass ratio of the precipitated silica to the fused silica    (precipitated silica/fused silica) contained in the oral composition    is 2.5-11:1.    Item 10-1.-   The oral composition according to any one of Items 1 to 9 for use in    the cleaning of the teeth.    Item 10-2.-   The oral composition according to any one of Items 1 to 9 for the    use in the removal of stains attached to the teeth.    Item 11.-   The oral composition according to any one of Items 1 to 10-2,    wherein the fused silica is fused silica in which particles having a    particle size greater than 60 μm are substantially removed.    Item 12.-   The oral composition according to any one of Items 1 to 11, wherein    the fused silica is fused silica sieved through a 60-μm mesh.    Item 13.-   The oral composition according to any one of Items 1 to 12, wherein    the RDA value is 90 to 140.    Item 14.-   The oral composition according to any one of Items 1 to 13,    comprising fused silica having different average particle sizes.    Item 15.-   The oral composition according to Item 14, comprising fused silica    having an average particle size of 0.1 to 10 μm and fused silica    having an average particle size greater than 10 μm and is equal to    or less than 45 μm.    Item 16.-   The oral composition according to Item 14 or 15, wherein the mass of    the fused silica having an average particle size of 0.1 to 10 μm    accounts for 10 to 90% of the total mass of the fused silica.    Item 17.-   The oral composition according to any one of Items 1 to 16, wherein    the dental abrasive has an RDA value of 20 to 200.    Item 18.-   The oral composition according to any one of Items 1 to 17, wherein    the degree of roundness of fused silica particles is 0.89 or more.-   Further, the present invention also encompasses stain removal    methods recited in the following items, for example.    Item A-1.-   A method for removing stains from a tooth with stains attached,    comprising the step of applying the oral composition recited in any    one of Items 1 to 13 in the oral cavity.    Item A-2.-   A method for removing stains from a tooth with stains attached,    comprising the step of brushing the teeth using the oral composition    recited in any one of Items 1 to 13.

The oral composition of the present invention has a high stain removalability and a low abrasive ability. Therefore, the risk of damaging theteeth by abrasion is low. Accordingly, the use of the oral compositionof the present invention makes it possible to remove stains in a highlyefficient manner, practically without damaging the teeth.

DETAILED DESCRIPTION

The present invention is described in more detail below.

The oral composition of the present invention comprises fused silica anda dental abrasive, and is used as a composition for cleaning the teeth.In particular, stains can be removed in a highly efficient manner, forexample, by brushing the teeth using the oral composition of the presentinvention. Further, when doing so, the problem of damage to the teeth byabrasion is very unlikely to occur.

As described above, fused silica is used in the field of semiconductors,and is either known or can be produced by a known method. Such fusedsilica can be used in the present invention. Fused silica can beobtained by, for example, fusing silicon dioxide powder as a rawmaterial (for example, silica powder) by flames at high temperatures(for example, 2,000 to 3,000° C.). Further, fused silica can also beobtained, for example, by oxidizing and dissolving silicon powder orcyclic siloxane by high-temperature flames. In this way, because fusedsilica is produced by a high-temperature treatment, the risk ofcontamination is low. Additionally, because silica is fused once andsolidified, silica particles have a high density and an increasedhardness. In particular, “thermally sprayed and fused silica (fusedsilica obtained by thermal spraying)”, which is obtained from crushedsilica powder as a raw material using a burner that sprays flames athigh temperatures and by the application of a thermal sprayingtechnique, can be preferably used as fused silica to be contained in theoral composition of the present invention. In particular, because thethermally sprayed and fused silica is obtained as a solid after most ofthe particles are fused, the hardness and the degree of sphericity arehigh. Therefore, as described below, the thermally sprayed and fusedsilica is particularly preferable as fused silica to be contained in theoral composition of the present invention. Although not particularlylimited, such thermally sprayed and fused silica can be preferablyproduced, for example, by a method disclosed in Japanese UnexaminedPatent Publication No. 562-241541.

Silica particles of the fused silica contained in the oral compositionof the present invention preferably have a high degree of sphericity(the shape is close to a complete sphere). The degree of sphericity canbe evaluated by “the degree of roundness,” which indicates how close thecontour of the globe is to a true circle. The degree of roundness can becalculated as follows: (i) first, an image of the target particle forthe measurement of the degree of roundness is taken, and the contour ofthe particle is traced to calculate the contour length and the area; and(ii) next, a circle having the same area as that of the contour of theparticle whose image was taken is drawn, and the circumferential lengthof the circle is calculated. At this time, the degree of roundness canbe determined by the following formula. The degree of roundness is 1when the contour of a particle is a true circle, and the degree ofroundness is never greater than 1.

${{Degree}\mspace{14mu}{of}\mspace{14mu}{roundness}} = \frac{{circumferential}\mspace{14mu}{length}\mspace{14mu}{calculated}\mspace{14mu}{in}\mspace{14mu}({ii})}{{contour}\mspace{14mu}{length}\mspace{14mu}{or}\mspace{14mu}{the}\mspace{14mu}{particle}\mspace{14mu}{calculate}\mspace{14mu}{in}\mspace{14mu}(i)}$

The degree of roundness can be measured using a roundness measuringinstrument (JIS B7451: 1997). A preferable instrument is one thatdisperses particles in a liquid such as water, allows the particles topass through the flow cell so as to take an image of the particles, andperforms analysis in a real-time manner. A particle image analyzer(FPIA-3000 by Sysmex Corporation) can be preferably used.

Fused silica particles contained in the oral composition of the presentinvention preferably have a degree of roundness of 0.89 or more, morepreferably 0.93 or more, and still more preferably 0.95 or more.

Further, the fused silica has a smaller BET specific surface areacompared to known dental abrasives (for example, wet silica such asprecipitated silica and silica gel). The fused silica contained in theoral composition of the present invention usually has a BET specificsurface area (m²/g) of 15 or less, preferably 10 or less, morepreferably 8 or less, and still more preferably 5 or less. The BETspecific surface area of silica can be measured using a Macsorb HMmodel-1201 (Mountech Co., Ltd.).

Further, the fused silica contained in the oral composition of thepresent invention preferably has a low oil absorption (linseed oilabsorption; JIS K5101). Specifically, the fused silica usually has anoil absorption (mL/100 g) of 20 or less, preferably 10 or less, morepreferably 8 or less, and still more preferably 5 or less.

It is believed that when fused silica has a smaller BET specific surfacearea, silica particles of the fused silica have a higher density and anincreased hardness. It is also believed that when fused silica has alower oil absorption, silica particles of the fused silica have a higherdensity and an increased hardness. Specifically, it is believed that thesmaller the BET specific surface area and the lower the oil absorptionof the fused silica, the higher the hardness of silica particles of thefused silica.

Commercially available fused silica may be purchased and used as thefused silica contained in the oral composition of the present invention.Purchases can be made from, for example, Denki Kagaku Kogyo KabushikiKaisha (commercially available as Denka fused silica (FB, FBX)), MicronInc. (commercially available as spherical silica), and the like.

When fused silica having a high hardness is added to the oralcomposition and applied in the oral cavity, it may leave a grittysensation in the oral cavity of the user. Such a sensation may not be aproblem to some users, but may undesirably provide an uncomfortablesensation to other users, as if stones or sand is inside their oralcavities; therefore, it is desirable to minimize such an uncomfortablesensation.

Such an uncomfortable sensation can be reduced by, for example, reducingthe amount of fused silica contained in the oral composition, andreducing the particle size of silica particles of the fused silicacontained in the oral composition.

Accordingly, although it is not particularly limited, silica particleshaving a relatively large particle size are preferably removed from thefused silica contained in the oral composition of the present invention.The removal can be performed by, for example, passing the particlesthrough a mesh.

Specifically, fused silica in which particles having a particle sizegreater than 60 μm are substantially removed is preferable. Fused silicain which particles having a particle size greater than 55 μm aresubstantially removed is more preferable. Herein, the phrase“substantially removed” does not mean that such particles are notcontained at all, but that a removal procedure is performed by, forexample, using a mesh or the like, so that such particles aresubstantially not contained.

In other words, the particle size of particles of the fused silicacontained in the oral composition of the present invention is preferably60 μm or less, and more preferably 55 μm or less. This also meansperforming a removal procedure by, for example, using a mesh or the likehaving a specific sieve size so that silica substantially has a specificparticle size or less. For example, fused silica comprising particles ofa particle size of 53 μm or less can be obtained by using a 53-μm mesh.Substantially, the particle size of the fused silica contained in theoral composition of the present invention is preferably 60 μm or less(more preferably 55 μm or less, still more preferably 53 μm or less, andstill yet more preferably 45 μm or less).

Specifically, the fused silica contained in the oral composition of thepresent invention is fused silica preferably sieved through a 60-μmmesh, more preferably a 55-μm mesh, still more preferably a 53-μm mesh,and still yet more preferably a 45-μm mesh. For example, such fusedsilica can be obtained by sieving commercially available fused silicathrough a specific-size mesh. Further, some of the commerciallyavailable fused silica has been already sieved, and such fused silicacan also be preferably used in the present invention.

Additionally, the fused silica contained in the oral composition of thepresent invention preferably has an average particle size (50%cumulative diameter; d50) of about 0.1 to about 45 μm, more preferablyabout 1 to about 20 μm, and still more preferably about 3 to about 17μm. Preferably, the fused silica obtained by removing silica particleshaving a large particle size has an average particle size (d50) in theabove-mentioned range.

The average particle size (d50) of the fused silica is a valuedetermined using water as a dispersion medium by a laser diffractionscattering measuring device. It can be measured by LA-920 (Horiba,Ltd.).

Further, the fused silica contained in the oral composition of thepresent invention has preferably a relative dentine abrasivity (RDA)value of 60 to 160 and more preferably 80 to 140. The RDA of the fusedsilica is the measurement obtained by preparing a slurry of fused silicaby the method described in “A. 3.6 Standard Abrasive Slurry” byISO11609: 1995, and by measuring the slurry by the method of Hefferen etal. (J. Dent. Res., Vol. 55, No. 4, 563-573, 1976).

Additionally, it is particularly preferable that different types offused silica having different average particle sizes are used incombination in the production of the oral composition of the presentinvention. Specifically, the fused silica contained in the oralcomposition of the present invention preferably comprises a mixture oftwo (or more) types of fused silica having different average particlesizes. When two (or more) types of fused silica having different averageparticle sizes are used in combination, it is possible to obtain an oralcomposition in which the stain removal ability is further enhanced, andthe stain removal ability is high relative to the abrasive ability.

For example, when two types of fused silica having different averageparticle sizes are used in combination, and when one having a smalleraverage particle size is referred to as fine fused silica and the otherone having a greater average particle size is referred to as coarsefused silica, the average particle size of the fine fused silica ispreferably 0.1 to 10 μm, more preferably 0.1 to 6 μm, and still morepreferably 0.2 to 3 μm, and the average particle size of the coarsefused silica is preferably greater than 10 μm and not greater than 45μm, more preferably 12 to 30 μm, and still more preferably 15 to 20 μm.Further, in this case, the content percentage of the fine fused silicais preferably 10 to 90% and more preferably 30 to 90% (or 30 to 80%),when the percentage of the total fused silica is assumed to be 100%.

The dental abrasive added to the oral composition of the presentinvention is a known dental abrasive. Examples of such dental abrasivesinclude precipitated silica (in particular, abrasive precipitatedsilica), silica gel, fumed silica, zircono-silicate, aluminum silicate,calcium phosphate, anhydrous dicalcium phosphate, dicalcium phosphatedihydrate, tricalcium phosphate, anhydrous calcium hydrogen phosphate,calcium hydrogen phosphate dihydrate, calcium pyrophosphate, calciumcarbonate, calcium sulfate, aluminum hydroxide, water-insoluble sodiummetaphosphate, trimagnesium phosphate, magnesium carbonate, titaniumoxide, polymethylmethacrylate, bentonite, hydroxyapatite, crystallinecellulose, synthetic resins (for example, polyethylene beads andpolypropylene beads), and the like. Of these, precipitated silica isparticularly preferable. Further, these dental abrasives can be usedsingly, or in a combination of two or more thereof.

These known dental abrasives have a larger BET specific surface areacompared to fused silica. The dental abrasive added to the oralcomposition of the present invention usually has a BET specific surfacearea (m²/g) of 20 to 1,000, preferably 20 to 400. Further, known dentalabrasives often have a higher oil absorption (linseed oil absorption,JIS K5101), compared to fused silica. The dental abrasive added to theoral composition of the present invention usually has an oil absorption(mL/100 g) of 20 to 400. Further, the dental abrasive added to the oralcomposition of the present invention preferably has a relative dentineabrasivity (RDA) value of 20 to 200. The RDA of the dental abrasive isthe measurement obtained by preparing a slurry of fused silica by themethod described in “A. 3.6 Standard Abrasive Slurry” by ISO11609: 1995,and by measuring the slurry by the method of Hefferen et al. (J. Dent.Res., Vol. 55, No. 4, 563-573, 1976).

The oral composition of the present invention preferably contains 0.25to 8.5% by mass of fused silica, more preferably 0.5 to 8.5% by mass,still more preferably 2 to 5% by mass, and still yet more preferably 3to 4.5% by mass, relative to the total composition. When the fusedsilica is contained in the above ranges, it is preferable not only fromthe viewpoint of the balance between the abrasive ability and the stainremoval ability, but also from the viewpoint of low risk of providingthe users the above-described uncomfortable sensation, as if stones orsand is inside their oral cavities, when they use the fused silica.

Further, the amount of the dental abrasive added to the oral compositionof the present invention can be suitably set according to the type ofthe dental abrasive. For example, preferably 2 to 70% by mass, morepreferably 5 to 60% by mass, of the dental abrasive is contained in thetotal composition. In particular, when precipitated silica is used asthe dental abrasive, the precipitated silica is contained in an amountof preferably 5 to 26% by mass, more preferably 7.5 to 26% by mass,still more preferably 7.5 to 22% by mass, still yet more preferably 15to 22% by mass, and particularly preferably 17 to 22% by mass, relativeto the total composition.

Further, when precipitated silica is used as the dental abrasive,precipitated silica and fused silica are preferably contained in a totalamount (i.e., the total content) of 10 to 34.5% by mass, more preferably15 to 34.5% by mass, relative to the total composition. Still further,when precipitated silica is used as the dental abrasive, the mass ratioof the precipitated silica to the fused silica (precipitatedsilica/fused silica) is preferably 2.5-11:1, preferably 3-11:1, and morepreferably 4-8:1.

The oral composition of the present invention containing the fusedsilica and the dental abrasive in the above ranges has, in particular, ahigh stain removal ability, although the abrasive ability thereof islow. Therefore, the use of the oral composition makes it possible tohighly efficiently remove stains without abrading the teeth more thannecessary.

The oral composition of the present invention containing the fusedsilica and the dental abrasive can be produced by a known method that isusually used to produce an oral composition.

Still further, the oral composition of the present invention can be usedfor the teeth or dentures, and can be formed into a dentifrice in any ofthe following forms by a common method: paste, powder, cream, gel,liquid, paste, and the like. In particular, a dentifrice in the form ofa paste, powder, cream, or gel is preferable.

The oral composition of the present invention can be produced by mixing,for example, a pharmaceutically or dental-hygienically acceptedsubstance, fused silica, and a dental abrasive (and other components, ifnecessary). Examples of such substrates include water, glycerol,ethylene glycol, diethylene glycol, polyethylene glycol, propyleneglycol, polypropylene glycol, sorbitol, xylitol, lactitol, mannitol,ethanol, and the like.

The oral composition of the present invention may contain othercomponents (optional components) that are usually added to oralcompositions.

For example, a non-ionic surfactant, an anionic surfactant, or azwitterionic surfactant may be added as a surfactant. Specifically,examples of non-ionic surfactants include fatty acid ester, fatty acidalkanolamides, sorbitan fatty acid ester, fatty acid monoglyceride,polyglycerol fatty acid ester, polyoxyethylene alkyl phenyl ether, alkylglycoside, diethyl sebacate, polyoxyethylene hydrogenated castor oil,polyoxyethylene sorbitan fatty acid ester, and the like. Examples ofanionic surfactants include alkyl sulfate salt, polyoxyethylene alkylether sulfate salt, alkyl sulfosuccinate, polyoxyethylene alkyl ethersulfosuccinate, N-acylamino acid salt, N-acyltaurine salt, alkyl ethercarboxylate, alkyl phosphate, polyoxyethylene alkyl ether phosphate,fatty acid monoglyceride sulfate, alkyl sulfoacetate, and the like.Examples of zwitterionic surfactants include alkyl dimethyl aminoacetatebetaine, alkyl amidopropyldimethyl aminoacetate betaine,N-acyl-N-carboxymethyl-N-hydroxyethylethylenediamine,N-alkylaminoethylglycine, and the like. These surfactants can be addedsingly, or in a combination of two or more thereof. The amount to beadded is usually 0.1 to 10% by mass relative to the total mass of thecomposition.

Examples of thickeners that can be added include cellulose derivativessuch as carrageenan, carboxymethyl cellulose, hydroxypropyl cellulose,hydroxypropyl methyl cellulose, and hydroxyethyl cellulose; gums such asxanthan gum, tragacanth gum, karaya gum, gum arabic, and gellan gum;synthetic binders such as polyvinyl alcohol, sodium polyacrylate,carboxy vinyl polymer, and polyvinylpyrrolidone; inorganic binders suchas thickening silica, aluminum silica gel, and veegum; sodium alginate;pectin; soybean polysaccharides; sodium chondroitin sulfate; sodiumhyaluronate; and the like. These thickeners can be added singly, or in acombination of two or more thereof. The thickener is usually added in anamount of 0.01 to 20% by mass.

Examples of flavoring agents that can be added include menthol,carboxylic acid, anethole, eugenol, methyl salicylate, limonene,ocimene, n-decyl alcohol, citronellal, α-terpineol, methyl acetate,citronellyl acetate, methyleugenol, cineol, linalool, ethyl linalool,thymol, spearmint oil, peppermint oil, lemon oil, orange oil, sage oil,rosemary oil, cinnamon oil, beefsteak plant oil, wintergreen oil, cloveoil, eucalyptus oil, pimento oil, d-camphor, d-borneol, fennel oil,cinnamon oil, cinnamaldehyde, mint oil, vanillin, and the like. Theseflavoring agents can be added singly, or in a combination of two or morethereof, usually in an amount of 0.01 to 1% by mass relative to thetotal mass of the composition.

Further, sweetening agents such as sodium saccharin, acesulfamepotassium, stevioside, neohesperidyl dihydrochalcone, glycyrrhizin,perillartine, thaumatin, asparatyl phenylalanyl methyl ester, andp-methoxycinnamic aldehyde can be added singly, or in a combination oftwo or more thereof; usually in an amount of 0.01 to 1% by mass relativeto the total mass of the composition.

Further, wetting agents such as sorbit, ethylene glycol, propyleneglycol, glycerol, 1,3-butylene glycol, polypropylene glycol, xylitol,maltitol, lactitol, Palatinit, and polyethylene glycol can be addedsingly, or in a combination of two or more thereof.

The oral composition of the present invention may contain an activeingredient. Examples thereof include cationic disinfectants such ascetylpyridinium chloride, benzalkonium chloride, benzethonium chloride,and chlorhexidine hydrochloride; vitamin E such as dl-α-tocopherolacetate, tocopherol succinate, and tocopherol nicotinate; amphotericdisinfectants such as dodecyldiaminoethylglycine; non-ionicdisinfectants such as triclosan and isopropylmethylphenol; enzymes suchas dextranase, amylase, protease, mutanase, lysozyme, and lytic enzyme;fluorides such as sodium monofluorophosphate, sodium fluoride, andstannous fluoride; tranexamic acid; epsilon aminocaproic acid; aluminumchlorohydroxy allantoin; dihydrocholesterol; glycyrrhetinic acid;glycerophosphate; chlorophyll; sodium chloride; calpeptide; dipotassiumglycyrrhizinate; allantoin; hinokitiol; potassium nitrate; and the like.These components may be added singly, or in a combination of two or morethereof.

Further, any container can be used to place the oral composition of thepresent invention therein without specific limitation. For example, acontainer made of glass, metal, plastic, a laminator material, or thelike may be used. Further, the shape of the container is also notparticularly limited. For example, a container such as a bottle, a cup,a pouch, or a tube can be used.

As described above, the oral composition of the present invention canhighly efficiently remove stains, even though the abrasive abilitythereof is not particularly high. The abrasive ability can bespecifically indicated by the relative dentine abrasivity (RDA) value.The abrasive ability (RDA value) of the oral composition of the presentinvention is preferably 200 or less, and more preferably 150 or less. Inparticular, the RDA value is preferably 90 to 140, and more preferably100 to 140. The RDA value is a value that indicates the degree ofabrasivity on dentine, and can be determined by the method of Hefferenet al. (J. Dent. Res., Vol. 55, No. 4, 563-573, 1976).

Further, the stain removal ability of the oral composition of thepresent invention can be determined by a modified method of the methodof Stooky et al. (J. Dent. Res., Vol. 61, No. 11, 1236-1239, 1982).Specifically, the stain removal ability can be measured by evaluatingthe color of the tooth surface using the L*a*b* color system as follows:when L*, a*, and b* values (respectively, L0, a0, and b0) of the toothsurface before staining, L*, a*, and b* values (respectively, L1, a1,and b1) of the tooth surface after staining, and L*, a*, and b* values(respectively, L2, a2, and b2) of the tooth surface after stain removalare measured, the stain removal ability (ΔE) can be calculated by thefollowing formula.Stain removal ability(ΔE)=100×(ΔE1/ΔE0),whereinΔE1=√{square root over ((L2−L1)²+(a2−a1)²+(b2−b1)²)}{square root over((L2−L1)²+(a2−a1)²+(b2−b1)²)}{square root over((L2−L1)²+(a2−a1)²+(b2−b1)²)}ΔE0=√{square root over ((L2−L0)²+(a2−a0)²+(b2−b0)²)}{square root over((L2−L0)²+(a2−a0)²+(b2−b0)²)}{square root over((L2−L0)²+(a2−a0)²+(b2−b0)²)}The L*, a*, and b* values can be measured using a colorimeter. A bovineenamel tooth fragment, for example, can be used as the tooth formeasurement. Additionally, it is preferable to mirror-polish the surfaceof the tooth fragment prior to measuring the tooth surface before beingdiscolored with stains. The L* value (i.e., L1) of the tooth surfaceafter being discolored with stains is preferably 30 or less. Whenremoving stains using an oral composition, it is preferable to soak thetooth fragment in the composition or its diluted solution (for example,2-fold or 3-fold dilution), and to brush (for example, an arbitraryvalue in the range of 100 to 2,000 strokes, preferably in the range of500 to 1,500 strokes, is set to brush the tooth surface). Brushing isperformed using a BSI-standard brushing machine equipped with a regulartoothbrush.

More specifically, the stain removal ability can be measured by a methoddescribed in the Examples.

The stain removal ability of the oral composition of the presentinvention, which can be measured as described, is preferably 25 orhigher, and more preferably 27 or higher.

The L*a*b* color system is a color system commonly used to describe thecolor of an object. The L*a*b* color system was standardized by theInternational Commission on Illumination (CIE) in 1976, and has beenincorporated into JIS (JIS Z8729) in Japan.

The ratio of the stain removal ability to the abrasive ability (stainremoval ability/abrasive ability) of the oral composition of the presentinvention is about 0.2 or greater, more preferably about 0.23 orgreater, and still more preferably 0.25 or greater.

The oral composition of the present invention is applicable not only tohumans, but also other animals (in particular, mammals) that have teeth.Examples of such animals include pets and farm animals, specifically,dogs, cats, monkeys, cows, horses, pigs, sheep, hamsters, rabbits, andthe like.

The present invention also encompasses a method for applying theabove-described oral composition in the oral cavity to remove stains onthe tooth. A method for applying the oral composition in the oral cavitycan be suitably selected according to the form of the oral composition,dosage form, and the like. For example, when the oral composition is aliquid (for example, a liquid tooth paste, a mouthwash, or the like),examples of methods include placing the oral composition in the oralcavity and rinsing the mouth. There is another example, for example, inwhich an appropriate amount of the oral composition (in particular, inthe solid or paste form) is placed on a toothbrush, and the teeth arebrushed. Stains on detached dentures can also be removed by the abovemethods. Further, the target of these methods is as described above, andit is not particularly limited to humans.

EXAMPLES

The present invention is described in detail below, but the presentinvention is not limited to the examples described below.

<Examination of Abrasive Ability and Stain Removal Ability>

Preparation of Oral Composition

An oral composition containing fused silica and a dental abrasive wasproduced as described below. Below, precipitated silica was used as adental abrasive.

<Silica>

The following fused silica and precipitated silica were used as silicato be contained in the oral composition. Fused silica sieved through a53 μm mesh was used.

Fused Silica (purchased from Micron Inc.)

BET specific surface area: 3.5 (m²/g)

Oil absorption (linseed oil absorption, JIS K5101): 5 (mL/100 g)

Degree of roundness: 0.95

Average particle size (d50): 14 μm

RDA: 130

Precipitated silica (purchased from Nihon Silica Kogyo, Ltd.)

BET specific surface area: 104 (m²/g)

Oil absorption (linseed oil absorption, JIS K5101): 110 (mL/100 g)

Degree of roundness: 0.69

Average particle size (d50): 12 μm

RDA: 100

These fused silica and precipitated silica were mixed with thecomponents described in Table 1, and the amount of silica contained waschanged, thereby producing an oral composition (paste-like dentifrice)of each example (Tables 2 to 4).

TABLE 1 Components Amount (mass %) Precipitated silica Shown in Tables 2to 5 Fused Silica Shown in Tables 2 to 5 Sorbitol 35 Glycerol 13 Sodiumlauryl sulfate 5 Disodium polyoxyethylene (2 mol) 5 alkyl (C12-14)sulfosuccinate polyoxyethylene hydrogenated castor oil 1 Sodiumcarboxymethyl cellulose 1 Sodium alginate 1 Purified water Balance Total100

The stain removal ability and the abrasive ability of the thus-obtainedoral composition of each example were examined in the following manner.

<Stain Removal Ability>

The stain removal ability (ΔE) was measured by a modified method of themethod of Stooky et al. (J. Dent. Res., Vol. 61, No. 11, 1236-1239,1982) and calculated. Specifically, the measurement and calculation werecarried out as follows using the L*a*b* color system.

A bovine enamel tooth fragment was cut out and embedded in transparentpolyester resin, and the surface of the tooth fragment wasmirror-polished. After washing with ion-exchange water, the toothfragment was fully dried, and L*, a*, and b* values were measured usinga colorimeter (CR-241 produced by Konica Minolta Sensing, Inc.). Thethus-obtained values were determined to be L0, a0, and b0, respectively.Further, the surface of the tooth fragment was etched by sequentiallyusing 0.2 M of hydrochloric acid, saturated sodium carbonate aqueoussolution, and 1% phytic acid aqueous solution; and then placed on astain application machine. Stains were applied for 7 days using anaqueous solution of a mixture of tea, coffee, and mucin from porcinestomach as a staining medium. On day 8 and onward, discoloration of thetooth fragment was continued until the L* value was 30 or below, byadding ferric chloride to the staining medium. After staining wasfinished, L*, a*, and b* values were measured using the colorimeter. Thevalues were determined to be L1, a1, and b1, respectively. The stainedtooth fragment was set in a BSI-standard brushing machine equipped witha regular toothbrush. The tooth fragment was brushed for 1,000 strokesin a 3-fold dilution of the oral composition of each of the Examples andComparative Examples. Subsequently, L*, a*, and b* values were measuredusing the colorimeter. The values were determined to be L2, a2, and b2,respectively. Then, a value expressed by the following formula wascalculated as the stain removal ability (ΔE) (rounded off to the nearestwhole number), and evaluated.Stain removal ability(ΔE)=100×(ΔE1/ΔE0),whereinΔE1=√{square root over ((L2−L1)²+(a2−a1)²+(b2−b1)²)}{square root over((L2−L1)²+(a2−a1)²+(b2−b1)²)}{square root over((L2−L1)²+(a2−a1)²+(b2−b1)²)}ΔE0=√{square root over ((L2−L0)²+(a2−a0)²+(b2−b0)²)}{square root over((L2−L0)²+(a2−a0)²+(b2−b0)²)}{square root over((L2−L0)²+(a2−a0)²+(b2−b0)²)}

The staining medium used herein and elsewhere was prepared by putting 4commercially available tea bags into about 1,200 mL of boiling water,boiling for 10 minutes, cooling to room temperature, adding 3.4 g ofcommercially available instant coffee and 2.5 g of mucin from porcinestomach (produced by Sigma-Aldrich Co. LLC) thereto, and uniformlystirring the mixture.

<Abrasive Ability (RDA Value)>

The RDA value was measured by the method of Hefferen et al. (J. Dent.Res., Vol. 55, No. 4, 563-573, 1976). This method is also described indetail in Japanese Unexamined Patent Publication No. 562-87507.Specifically, the measurement was performed as follows: 8 human teethwere provided in advance, and the dentine was irradiated withradioactive ³²P (phosphorus-32), held using resin, and set in an 8-headabrasive machine under a brushing load of 150 g. Next, 40 mL of tapwater was added to 25 g of the oral composition of each of the Examplesand Comparative Examples, and well-mixed slurry was placed in each tankof the polishing machine and polished for 1,500 strokes. 3 mL ofpolished slurry was poured into a metal plate mold, and dried overnightwhile circulating the air at 60° C. The radioactivity of the surface ofthe thus-prepared dried slurry plate was measured. Using a dentinetreated in the same manner as described above, slurry obtained bydissolving 100 g of calcium pyrophosphate in 50 mL of an aqueoussolution of 0.5% carboxymethyl cellulose was measured in the same mannerand regarded as a control example. Assuming the radiation dose in thecontrol example to be 100, the value of each tank was calculated, andthe average of 8 values was regarded as the RDA value.

The RDA value was used as an index of the abrasive ability. Hereinafter,the RDA value is regarded as the value of the abrasive ability.

Tables 2 to 5 summarize the results. The values described in the columns“Precipitated Silica” and “Fused Silica” indicate the amount (mass %) ofthese precipitated silica and fused silica added to each oralcomposition.

Further, Tables 2 to 5 also show the values of the ratio of stainremoval ability to abrasive ability (stain removal ability/abrasiveability) of the oral composition of each Example. An oral compositionwhose removal ability is high relative to the abrasive ability (i.e., anoral composition having a greater ratio (stain removal ability/abrasiveability)) can be evaluated as a better oral composition.

TABLE 2 Comparative Example Example Example Example Example ExampleExample Example Example Example 1 1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 1-9Precipitated 17 17 17 17 17 17 17 17 17 17 silica Fused silica 0 0.5 22.5 3 3.5 4.5 6 8.5 10 Stain removal 20 25 27 32 32 35 36 30 30 27ability Abrasive 103 103 103 114 109 110 120 132 132 132 ability Stainremoval 0.19 0.24 0.26 0.28 0.29 0.32 0.30 0.23 0.23 0.20ability/abrasive ability

TABLE 3 Comparative Example Example Example Example Example ExampleExample Example Example 2 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 Precipitated 05 7.5 15 17 20 22 24 26 silica Fused silica 3 3 3 3 3 3 3 3 3 Stainremoval 20 24 25 27 32 35 41 33 30 ability Abrasive ability 89 100 98109 109 120 130 140 130 Stain removal 0.22 0.24 0.26 0.25 0.29 0.29 0.320.24 0.23 ability/abrasive ability

TABLE 4 Example Example Example Example Example Example 3-1 3-2 3-3 3-43-5 3-6 Precipitated silica 22 22 22 22 22 22 Fused silica 0.25 0.5 2.53 4.5 6.0 Stain removal ability 25 27 35 41 33 29 Abrasive ability 93 90140 130 106 121 Stain removal 0.27 0.30 0.25 0.32 0.31 0.24ability/abrasive ability

TABLE 5 Comparative Comparative Comparative Example 3 Example 4 Example5 Example 4 Example 5 Example 6 Example 7 Precipitated silica 0 24 3021.5 24 24 26 Fused silica 2.5 0 0 3.5 3.5 6.0 3.5 Stain removal ability20 21 23 46 28 28 29 Abrasive ability 79 123 153 127 127 117 132 Stainremoval 0.25 0.17 0.15 0.36 0.22 0.24 0.22 ability/abrasive ability

As shown in Table 2, in the case where 17% by mass of precipitatedsilica was added to the total mass of the oral composition, the stainremoval ability was 25 or greater when the fused silica was addedthereto. In particular, when 0.5 to 8.5% by mass of the fused silica wasadded, the stain removal ability was 25 or greater, and the ratio ofstain removal ability to abrasive ability (stain removalability/abrasive ability) was about 0.23 or greater, thus indicatingthat a more preferable oral composition can be obtained.

Further, as shown in Table 3, in the case where 3% by mass of fusedsilica was added to the total mass of the oral composition, the stainremoval ability was 24 or greater when the precipitated silica was addedthereto. In particular, when 7.5 to 26% by mass of the precipitatedsilica was added, the stain removal ability was 25 or greater, and theratio (stain removal ability/abrasive ability) was about 0.23 orgreater, thus indicating that a more preferable oral composition can beobtained.

Additionally, as shown in Table 4, in the case where 22% by mass offused silica was added to the total mass of the oral composition, thestain removal ability was 25 or greater when the precipitated silica wasadded thereto. Specifically, when at least 0.25 to 6% by mass of thefused silica was added, the stain removal ability was 25 or greater, andthe ratio (stain removal ability/abrasive ability) was about 0.24 orgreater, thus indicating that a preferable oral composition can beobtained.

Further, it became clear from all Comparative Examples that an oralcomposition whose stain removal ability is 24 or greater cannot beobtained when the oral composition was produced by adding only fusedsilica or precipitated silica.

Additionally, it became clear from all Examples, that an oralcomposition comprising fused silica and precipitated silica ispreferable because at least the stain removal ability thereof is 24 orgreater; an oral composition comprising 0.25 to 8.5% by mass (or 0.5 to8.5% by mass) of fused silica and 5 to 26% by mass (or 7.5 to 26% bymass) of precipitated silica is more preferable because the stainremoval ability thereof is 25 or greater, and the ratio (stain removalability/abrasive ability) is about 0.24 or greater; and an oralcomposition comprising 2 to 4.5% by mass of fused silica and 15 to 22%by mass of precipitated silica is still more preferable because thestain removal ability thereof is 27 or greater, and the ratio (stainremoval ability/abrasive ability) is about 0.25 or greater.

In the tables, Example 1-4 and Example 2-4 are the same, and Example 2-6and Example 3-4 are the same.

[Examination of the Elimination of Uncomfortable Sensation at the Timeof Use]

The oral composition containing fused silica may leave a gritty,uncomfortable sensation in the oral cavity (uncomfortable sensation asif stones or sand is inside the oral cavity) when the oral compositionis applied into the oral cavity (for example, placing the oralcomposition on a toothbrush to brush the teeth), as described above.Such a sensation may not be a problem to some users, but it is not verydesirable. Therefore, a preferable particle size and amount of fusedsilica to be added to the oral composition were examined in view of theuncomfortable sensation.

<Examination of the Particle Size of Fused Silica>

This examination was performed using the fused silica used in theabove-described examination of the abrasive ability and the stainremoval ability. The fused silica was sieved through meshes of varioussizes shown in Table 7, and silica particles having a large particlesize were removed. Then, using fused silica obtained after the removalprocedure, oral compositions (Reference Examples 1 to 4) were preparedin accordance with the composition shown in the prescription (Table 6)described below. The abrasive precipitated silica in the prescriptionbelow is the same precipitated silica used in the above-describedexamination of the abrasive ability and the stain removal ability.Further, the thickening precipitated silica in the prescription belowhas an oil absorption of 335 (mL/100 g) and a BET specific surface areaof 236 (m²/g).

TABLE 6 Prescription: Composition of Reference Examples 1 to 4Components Amount (mass %) Fused silica (mesh diameter is shown 5.0 inTable 7) Abrasive Precipitated silica 13.0 Thickening precipitatedsilica 1.0 Sorbitol 24.0 Glycerol 5.0 Polyethyleneglycol 400 5.0 Xanthangum 0.5 Carboxymethyl cellulose 0.7 Sodium lauryl sulfate 1.2 Flavoring1.0 Sodium saccharin 0.2 Purified water Balance Total 100

Subjects evaluated the sensation when they brushed their teeth by usingan appropriate amount of each oral composition (Reference Examples 1 to4) with the toothbrush. Specifically, 10 subjects brushed their teethusing each oral composition, and selected one out of the three followinglevels with respect to the question “how much of a gritty sensation didyou feel?”

-   “I felt no such sensation at all.” (3 points)-   “I felt such a sensation, but it was not uncomfortable.” (2 points)-   “I felt an uncomfortable sensation.” (1 point)    Consequently, the average point of 10 people was calculated. An    average point of 2.5 or higher was evaluated as “I”, an average    point of 2 or more and less than 2.5 was evaluated as “II”, and an    average point of less than 2 was evaluated as “III”. Table 7 also    shows the results.

TABLE 7 Mesh size (μm) used to remove particles having a Evaluation ofthe large particle size sensation Reference 150 III Example 1 (averagepoint: 1.5) Reference 75 II Example 2 (average point: 2.3) Reference 53I Example 3 (average point: 2.7) Reference 45 I Example 4 (averagepoint: 2.9)

It was found that there was no particular problem in the sensation whenan oral composition containing fused silica in which particles of alarge particle size were removed (i.e., fused silica was sieved) using a75-μm mesh or smaller was used. It was also found that a good sensationcan be obtained when an oral composition containing fused silica inwhich particles of a large particle size were removed (i.e., fusedsilica was sieved) using a 53-μm mesh or smaller was used.

<Examination of the Amount of Fused Silica>

Oral compositions of Reference Example 3.1, Reference Example 3.2, andReference Example 3.3 were prepared in the same manner as in thepreparation of the oral composition of Reference Example 3 above, exceptthat the amount of silica was changed. Specifically, silica contained inthese Reference Examples is fused silica in which particles having alarge particle size were removed (i.e., sieved) using a 53-μm mesh.Table 8 shows the amount of silica (mass %) relative to the total massof the composition in each Reference Example.

Further, the sensation was evaluated in the same manner described above.Table 8 also shows the results.

TABLE 8 Amount of silica Evaluation of the contained (mass %) sensationReference 15 III Example 3.3 (average point: 1.6) Reference 10 IIExample 3.2 (average point: 2.1) Reference 7.5 I Example 3.1 (averagepoint: 2.5) Reference 5 I Example 3 (average point: 2.7)

It was found that there was no particular problem in the sensation atleast when the amount of fused silica contained was 10% by mass or less.It was also found that a good sensation can be obtained when the amountof fused silica contained was 7.5% by mass or less.

[Examination of the Combination of Different Types of Fused SilicaHaving Different Particle Sizes]

How the properties of the oral composition change by the use of two (ormore) types of fused silica having different particle sizes incombination was examined.

The target oral composition of the examination was produced based on thecomposition described in Table 1, except that the amount (mass %) ofprecipitated silica and the amount (mass %) of fused silica were inaccordance with the values described in Tables 9 and 10 below.

Fused silica used for the production of the oral composition is amixture of fused silica (powder) having a relatively small averageparticle size and fused silica (powder) having a relatively largeaverage particle size. Hereafter, the former is also referred to as finefused silica, and the latter is also referred to as coarse fused silica.

The average particle size herein is a median diameter (d50), and is thevalue measured using a laser diffraction scattering measuring device(LA-920, produced by Horiba, Ltd.). The average particle size of finefused silica is 3.1 μm, and the distribution range thereof is 0.1 to 10μm. The average particle size of coarse fused silica is 17.4 μm, and thedistribution range thereof is 10 to 45 μm. Tables 9 and 10 also show theamount (mass %) of fine fused silica and coarse fused silica containedin the oral composition.

The stain removal ability, the abrasive ability, and the ratio (stainremoval ability/abrasive ability) of each oral composition produced weremeasured in the same manner described in “Examination of AbrasiveAbility and Stain Removal Ability” above. Tables 9 and 10 also showthese results.

TABLE 9 Exam- Exam- ple ple Example Example Example A-1 A-2 A-3 A-4 A-5Precipitated 22 22 22 22 22 silica Fused Amount 3 3 3 3 3 silica Fine 00.3 0.9 2.7 3 powder (3.1 μm) Coarse 3 2.7 2.1 0.3 0 powder (17.4 μm)Stain removal 29 34 41 42 36 ability Abrasive ability 110 120 130 141135 Stain removal 0.26 0.29 0.32 0.30 0.27 ability/abrasive ability

TABLE 10 Example B-1 Example B-2 Example B-3 Precipitated silica 17 1717 Fused Amount 3 3 3 silica Fine powder 0.9 2.4 2.7 (3.1 μm) Coarsepowder 2.1 0.6 0.3 (17.4 μm) Stain removal ability 32 36 39 Abrasiveability 109 115 130 Stain removal 0.29 0.31 0.30 ability/abrasiveability

In the production of each oral composition, the percentages of finefused silica relative to the total fused silica used in Examples A-1,A-2, A-3, A-4, and A-5 were 0, 10, 30, 90, and 100%, respectively. Thepercentages thereof in Examples B-1, B-2, and B-3 were 30, 80, and 90%,respectively.

It was found from Tables 9 and 10 that the stain removal ability wasgreater and the ratio (stain removal ability/abrasive ability) washigher when fine fused silica and coarse fused silica were used incombination, than when used singly. Specifically, it was found to bemore preferable when 30 to 90% of fine fused silica was contained in thetotal fused silica used, because the stain removal ability was evengreater and the ratio (stain removal ability/abrasive ability) wasincreased.

Prescription examples of the oral composition of the present inventionare shown below. The amount (%) in each prescription example indicatesmass %. In the following prescription examples, 7 types of fused silica(fused silica A to G) are used, and all of these are fused silica(thermally sprayed and fused silica) produced by a spraying method. Themesh size for sieving fused silica A to G, the degree of roundness, theBET specific surface area, and the oil absorption (linseed oilabsorption; JIS K5101) are as follows.

-   Fused silica A: mesh size of 60 (μm), degree of roundness of 0.90,    BET specific surface area of 10.0 (m²/g), and oil absorption of 9.8    (mL/100 g)-   Fused silica B: mesh size of 55 (μm), degree of roundness of 0.93,    BET specific surface area of 8.0 (m²/g), and oil absorption 7.7 of    (mL/100 g)-   Fused silica C: mesh size of 53 (μm), degree of roundness of 0.95,    BET specific surface area of 5.0 (m²/g), and oil absorption of 3.5    (mL/100 g)-   Fused silica D: mesh size of 45 (μm), degree of roundness of 0.98,    BET specific surface area of 4.6 (m²/g), and oil absorption of 3.2    (mL/100 g)-   Fused silica E: mesh size of 60 (μm), degree of roundness of 0.94,    BET specific surface area of 6.0 (m²/g), and oil absorption 5.5    (mL/100 g)-   Fused silica F: mesh size of 55 (μm), degree of roundness of 0.97,    BET specific surface area of 4.8 (m²/g), and oil absorption of 3.3    (mL/100 g)-   Fused silica G: mesh size of 53 (μm), degree of roundness of 0.91,    BET specific surface area of 9.1 (m²/g), and oil absorption of 8.3    (mL/100 g)

TABLE 11 <Prescription Example 1> Dentifrice Components Amount (%) Fusedsilica A 2.0 Crystalline cellulose 18.0 Thickening precipitated silica5.0 Sorbitol 40.0 Xanthan gum 0.6 Sodium pyrophosphate 3.0 Sodiumphosphate 0.5 Sodium hydrogen phosphate 0.2 Sodium fluoride 0.2Triclosan 0.1 Titanium oxide 0.5 Sodium lauryl sulfate 1.0 Flavoring 1.0Sodium saccharin 0.2 Purified Water Balance Total 100.0

TABLE 12 <Prescription Example 2> Dentifrice Components Amount (%) Fusedsilica B 4.5 Calcium hydrogen phosphate 13.0 Xanthan gum 0.6 Sodiumpolyacrylate 0.3 Sodium monofluorophosphate 0.7 Potassium nitrate 5.0Tocopherol nicotinate 0.05 Glyceryl monostearate 1.2 Flavoring 1.0Sodium saccharin 0.2 Reduced palatinose 5.0 Purified Water Balance Total100.0

TABLE 13 <Prescription Example 3> Dentifrice Components Amount (%) Fusedsilica C 6.0 Calcium carbonate 15.0 Thickening precipitated silica 6.0Glycerol 10.0 Xanthan gum 0.7 Sodium carboxymethyl cellulose 0.5 Sodiumpolyacrylate 0.4 Sodium monofluorophosphate 0.7 Tocopherol acetate 0.1Sodium lauroyl sarcosine 0.1 Sodium lauryl sulfate 1.0 Methylparaben 0.1Flavoring 1.0 Sodium saccharin 0.2 Purified Water Balance Total 100.0

TABLE 14 <Prescription Example 4> Dentifrice Components Amount (%) Fusedsilica D 7.5 Aluminium hydroxide 20.0 Thickening precipitated silica 8.0Glycerol 20.0 Sodium carboxymethyl cellulose 0.7 Sodiummonofluorophosphate 0.7 Dipotassium glycyrrhizinate 0.02 Polyoxyethylene(60) hydrogenated castor oil 1.0 Alkyl (8-16) glucoside 1.0 Flavoring1.0 Sodium saccharin 0.05 L-Menthol 0.5 Purified Water Balance Total100.0

TABLE 15 <Prescription Example 5> Dentifrice Components Amount (%) Fusedsilica E 8.5 Thickening precipitated silica 6.0 Glycerol 20.0Hydroxyethyl cellulose 0.7 Carrageenan 0.3 Sodium alginate 0.7 Sodiummonofluorophosphate 0.7 Dipotassium glycyrrhizinate 0.02 Polyoxyethylene(60) hydrogenated castor oil 1.0 Alkyl (8-16) glucoside 1.5 Flavoring1.0 Sodium saccharin 0.05 Reduced palatinose 10.0 Purified Water BalanceTotal 100.0

TABLE 16 <Prescription Example 6> Dentifrice Components Amount (%) Fusedsilica F 0.5 Abrasive precipitated silica 18.0 Polyethylene powder 3.0Sorbitol 20.0 Glycerol 8.0 Polyethyleneglycol 200 3.0 Xanthan gum 0.7Sodium carboxymethyl cellulose 0.7 Sodium hydroxide 1.0 Erythritol 0.5Tocopherol acetate 0.1 Triclosan 0.1 Propylene glycol monostearate 1.0Titanium oxide 0.5 Flavoring 1.0 Sodium saccharin 0.2 L-Menthol 0.5Purified Water Balance Total 100.0

TABLE 17 <Prescription Example 7> Dentifrice Components Amount (%) Fusedsilica G 0.5 Abrasive silica gel 18.0 Silylated precipitated silica 2.0Sorbitol 25.0 Polyethyleneglycol 600 3.0 Xanthan gum 0.7 Sodiumcarboxymethyl cellulose 0.7 Sodium hydroxide 1.0 Phytic acid 0.5Tocopherol acetate 0.1 Triclosan 0.1 Sodium lauryl sulfate 1.0 Titaniumoxide 0.5 Flavoring 1.0 Sodium saccharin 0.2 L-Menthol 0.5 PurifiedWater Balance Total 100.0

TABLE 18 <Prescription Example 8> Dentifrice Components Amount (%) Fusedsilica A 7.5 Abrasive precipitated silica 5.0 Calcium hydrogen phosphatefor toothpaste 10.0 Glycerol 8.0 Polyethyleneglycol 1000 3.0 Sodiumcarboxymethyl cellulose 0.7 Magnesium phosphate 0.5 Hydroxyapatite 2.0Sodium lauroyl sarcosine 1.0 Zeolite 0.5 Glyceryl monostearate 1.2Flavoring 1.0 Sodium saccharin 0.2 Purified Water Balance Total 100.0

TABLE 19 <Prescription Example 9> Dentifrice Components Amount (%) Fusedsilica B 1.0 Abrasive precipitated silica 18.0 Cellulose powder 5.0Sorbitol 20.0 Polyethyleneglycol 1500 3.0 Carrageenan 0.7 Glycerol fattyacid ester 1.0 Potassium hydroxide solution 1.0 DL-malic acid 0.5 Sodiumfluoride 0.2 Sodium lauryl sulfate 1.0 Titanium oxide 0.5 Flavoring 1.0Sodium saccharin 0.2 L-Menthol 0.5 Purified Water Balance Total 100.0

TABLE 20 <Prescription Example 10> Dentifrice Components Amount (%)Fused silica A 5.0 Fused silica C 3.0 Sorbitol 20.0 Polyethyleneglycol2000 3.0 Sodium fluoride 0.2 Sodium lauryl sulfate 1.0 Titanium oxide0.5 Mica 1.0 Flavoring 1.0 Sodium saccharin 0.2 Mint oil 0.5 PurifiedWater Balance Total 100.0

TABLE 21 <Prescription Example 11> Dentifrice Components Amount (%)Fused silica D 6.5 Abrasive precipitated silica 8.0 Tricalcium phosphate5.0 Calcium hydrogen phosphate 10.0 Sorbitol 20.0 Ethanol 5.0Polyethyleneglycol 400 3.0 Magnesium phosphate 0.5 Sodium carboxymethylcellulose 0.7 Sodium monofluorophosphate 0.7 Zeolite 0.5 ε-aminocaproicacid 0.1 Sodium lauryl sulfate 1.0 Paraben 0.1 Flavoring 1.0 Xylitol 0.2L-Menthol 0.5 Purified Water Balance Total 100.0

TABLE 22 <Prescription Example 12> Dentifrice Components Amount (%)Fused silica E 3.0 Abrasive precipitated silica 18.0 Thickeningprecipitated silica 1.0 Sorbitol 20.0 Glycerol 8.0 Propylene glycol 5.0Polyethyleneglycol 4000 3.0 Sodium carboxymethyl cellulose 0.7 Sodiumfluoride 0.2 Isopropylmethylphenol 0.05 Sodium lauryl sulfate 1.0Polyoxyethylene (2 mol) Alkyl (12-14) 1.0 disodium sulfosuccinatePolyoxyethylene (60) hydrogenated castor oil 1.0 Titanium oxide 0.5Flavoring 1.0 Sodium saccharin 0.2 Stevia extract 0.1 Purified WaterBalance Total 100.0

TABLE 23 <Prescription Example 13> Dentifrice Components Amount (%)Fused silica F 2.5 Thickening precipitated silica 3.0 Sorbitol 20.0Propylene glycol 8.0 Xanthan gum 0.7 Sodium hydrogen carbonate 0.5Sodium monofluorophosphate 0.7 Sodium lauroyl sarcosine 1.0 Dextranase0.5 Sodium lauryl sulfate 1.0 Paraben 0.1 DL-Alanine 0.5 Flavoring 1.0Sodium saccharin 0.2 L-Menthol 0.5 Purified Water Balance Total 100.0

TABLE 24 <Prescription Example 14> Dentifrice Components Amount (%)Fused silica G 2.5 Aluminium hydroxide 8.0 Thickening precipitatedsilica 3.0 Sorbitol 20.0 Propylene glycol 8.0 Xanthan gum 0.7 2-AlkylN-hydroxyethylimidazolinium betain 0.5 Sodium hydrogen carbonate 0.5Sodium monofluorophosphate 0.7 Sodium lauroyl sarcosine 1.0 Dextranase0.5 Sodium lauryl sulfate 1.0 Paraben 0.1 Titanium oxide 0.5 Flavoring1.0 Sodium saccharin 0.2 L-Menthol 0.5 Purified Water Balance Total100.0

TABLE 25 <Prescription Example 15> Dentifrice Amount Components (%)Fused silica A 8.0 Abrasive silica gel 5.0 Sorbitol 20.0 Xanthan gum 0.7Sodium polyphosphate 0.7 Sodium alginate 0.7 Sodium fluoride 0.2 Sodiumlauroyl sarcosine 1.0 Hydroxyethyl cellulose dimethyl diallyl ammoniumchloride 0.2 Benzalkonium chloride 0.1 Sodium lauryl sulfate 0.5Polyoxyethylene (60) hydrogenated castor oil 1.0 Titanium oxide 0.5Flavoring 1.0 Xylitol 0.2 L-Menthol 0.5 Purified Water Balance Total100.0

TABLE 26 <Prescription Example 16> Dentifrice Components Amount (%)Fused silica B 1.5 Abrasive precipitated silica 20.0 Thickening fumedsilica 5.0 Sorbitol 20.0 Propylene glycol 8.0 Polyethyleneglycol 60003.0 Xanthan gum 0.7 Sodium fluoride 0.2 Isopropylmethylphenol 0.05ε-aminocaproic acid 0.1 Sodium lauryl sulfate 1.0 Titanium oxide 0.5Flavoring 1.0 Sodium saccharin 0.2 L-Menthol 0.5 Purified Water BalanceTotal 100.0

TABLE 27 <Prescription Example 17> Dentifrice Components Amount (%)Fused silica C 4.0 Calcium carbonate 15.0 Abrasive precipitated silica5.0 Sorbitol 20.0 Glycerol 5.0 Sodium carboxymethyl cellulose 0.7Polyoxyethylene sorbitan monostearate 0.5 Sodium hydroxide 0.5 Sodiumchloride 15.0 Sodium monofluorophosphate 0.7 β-glycyrrhetinate 0.02Sodium lauryl sulfate 1.0 Titanium oxide 0.5 Flavoring 1.0 Sodiumsaccharin 0.2 Purified Water Balance Total 100.0

TABLE 28 <Prescription Example 18> Dentifrice Components Amount (%)Fused silica D 4.0 Abrasive precipitated silica 10.0 Sorbitol 20.0Carrageenan 0.7 Sodium carboxymethyl cellulose 0.7 SodiumN-lauroyl-L-glutamate 0.5 Sodium hydrogen carbonate 0.007 Sodiumchloride 10.0 Sodium monofluorophosphate 0.7 Benzethonium chloride 0.1Sodium lauryl sulfate 1.0 Titanium oxide 0.5 Flavoring 1.0 Sodiumsaccharin 0.2 Purified Water Balance Total 100.0

TABLE 29 <Prescription Example 19> Dentifrice Components Amount (%)Fused silica E 5.5 Silica gel 10.0 Calcium carbonate 5.0 Zinc oxide 1.0Sorbitol 20.0 Polyethyleneglycol 11000 3.0 Sodium carboxymethylcellulose 0.7 Sodium monofluorophosphate 0.7 Benzethonium chloride 0.1Sodium lauryl sulfate 1.0 Flavoring 1.0 Sodium saccharin 0.2 PurifiedWater Balance Total 100.0

TABLE 30 <Prescription Example 20> Dentifrice Components Amount (%)Fused silica F 3.5 Abrasive precipitated silica 15.0 Zinc oxide 1.0Sorbitol 20.0 Glycerol 5.0 Polyethyleneglycol 20000 3.0 Polyethylenepowder 0.5 Xanthan gum 0.7 Sodium carboxymethyl cellulose 0.7Cocamidopropyl betaine 0.5 Sodium hydroxide 0.5 Sodium tripolyphosphate0.3 Sodium pyrophosphate 0.2 Sodium monofluorophosphate 0.7 Sodiumlauryl sulfate 1.0 Titanium oxide 0.5 Flavoring 1.0 Sodium saccharin 0.2Purified Water Balance Total 100.0

TABLE 31 <Prescription Example 21> Dentifrice Components Amount (%)Fused silica G 3.5 Abrasive precipitated silica 15.0 Sorbitol 20.0Propylene glycol 3.0 Carrageenan 0.7 Sodium carboxymethyl cellulose 0.7Sodium hydroxide 0.5 Methylvinylether/maleic acid copolymer 0.5 Sodiumfluoride 0.2 Triclosan 0.1 Sodium lauryl sulfate 1.0 Titanium oxide 0.5Flavoring 1.0 Sodium saccharin 0.2 Purified Water Balance Total 100.0

TABLE 32 <Prescription Example 22> Dentifrice Components Amount (%)Fused silica A 3.5 Silica gel 15.0 Sorbitol 10.0 Glycerol 5.0Polyethyleneglycol 300 5.0 Xanthan gum 0.7 Sodium carboxymethylcellulose 0.7 Sodium hydroxide 0.5 Sodium metaphosphate 0.5Cocamidopropyl betaine 0.3 Carbomer 956 0.3 Poloxamer 407 0.2 Sodiummonofluorophosphate 0.7 Sodium lauryl sulfate 1.0 Titanium oxide 0.5Flavoring 1.0 Sodium saccharin 0.2 Purified Water Balance Total 100.0

TABLE 33 <Prescription Example 23> Dentifrice Components Amount (%)Fused silica B 3.5 Abrasive precipitated silica 15.0 Sorbitol 10.0Polyethyleneglycol 1540 5.0 Xanthan gum 1.0 Sodium monohydrogenphosphate (anhydrous) 0.5 Sodium benzoate 0.5 Sodium fluoride 0.2 Sodiumpolyoxyethylene lauryl ether sulfate 1.0 Titanium oxide 0.5 Mica 0.2Flavoring 1.0 Sodium saccharin 0.2 Purified Water Balance Total 100.0

TABLE 34 <Prescription Example 24> Dentifrice Components Amount (%)Fused silica C 3.5 Abrasive silica gel 15.0 Sorbitol 10.0 Glycerol 5.0Polyethyleneglycol 400 5.0 Sodium carboxymethyl cellulose 0.7 Sodiummonohydrogen phosphate (anhydrous) 1.0 Lecithin 0.5Methylvinylether/maleic acid copolymer 0.5 Sodium fluoride 0.2 Sodiumlauryl sulfate 1.0 Mica 0.2 Flavoring 1.0 Sodium saccharin 0.2 Limonene0.5 Purified Water Balance Total 100.0

TABLE 35 <Prescription Example 25> Dentifrice Components Amount (%)Fused silica D 3.5 Abrasive precipitated silica 15.0 Glycerol 5.0Propylene glycol 5.0 Polyethyleneglycol 400 5.0 Xanthan gum 0.7 Sodiumcarboxymethyl cellulose 0.7 Calcium peroxide 1.0 Sodium hydrogencarbonate 0.5 Sodium hydroxide 0.5 Poloxamer 407 0.3 Potassiumpyrophosphate 0.2 Sodium monofluorophosphate 0.7 Sodium lauryl sulfate1.0 Titanium oxide 0.5 Flavoring 1.0 Sodium saccharin 0.2 Purified WaterBalance Total 100.0

TABLE 36 <Prescription Example 26> Dentifrice Amount Components (%)Fused silica E 3.5 Abrasive precipitated silica 15.0 Glycerol 5.0Polyethyleneglycol 4000 5.0 Carrageenan 0.7 Polyvinylpyrrolidone 0.5Sodium polyphosphate 0.7 Hydroxyethyl cellulose dimethyl diallylammonium chloride 0.2 Sodium monofluorophosphate 0.7 Sodium laurylsulfate 1.0 Polyoxyethylene (60) hydrogenated castor oil 0.5 Titaniumoxide 0.5 Flavoring 1.0 Sodium saccharin 0.2 Purified Water BalanceTotal 100.0

TABLE 37 <Prescription Example 27> Dentifrice Components Amount (%)Fused silica F 3.5 Abrasive precipitated silica 15.0 Glycerol 5.0Polyethyleneglycol 4000 5.0 Carrageenan 0.7 Polyvinylpyrrolidone 0.5Sodium polyphosphate 0.7 Sodium monofluorophosphate 0.7 Sodium laurylsulfate 1.0 Coconut oil fatty acid amide propyl betaine 1.0Polyoxyethylene (60) hydrogenated castor oil 0.5 Polyoxyethylene stearylether 0.5 Titanium oxide 0.5 Flavoring 1.0 Sodium saccharin 0.2Anhydrous caffeine 0.1 Purified Water Balance Total 100.0

TABLE 38 <Prescription Example 28> Dentifrice Components Amount (%)Fused silica G 3.5 Calcium carbonate 5.0 Abrasive precipitated silica15.0 Glycerol 5.0 Propylene glycol 5.0 Polyethyleneglycol 1540 5.0 Agarpowder 1.0 Sodium carboxymethyl cellulose 0.7 Hydrogen peroxide 0.5Sodium monofluorophosphate 0.7 Benzethonium chloride 0.5N-stearoyl-N-methyltaurine sodium 0.5 Sodium lauryl sulfate 1.0 Titaniumoxide 0.5 Flavoring 1.0 Sodium saccharin 0.2 Purified Water BalanceTotal 100.0

The invention claimed is:
 1. An oral composition comprising: a mixture of fused silica in an amount of 2 to 4.5% by mass, the mixture of fused silica including first fused silica having an average particle size of 0.1 to 10 μm and a second fused silica having an average particle size greater than 10 μm and equal to or less than 45 μm; and precipitated silica in an amount of 15 to 22 % by mass.
 2. The oral composition according to claim 1, wherein the BET specific surface area of the fused silica is 10 m²/g or less.
 3. The oral composition according to claim 1, wherein the fused silica has an oil absorption of 20 mL/100 g or less.
 4. The oral composition according to claim 1, wherein the mass ratio of the precipitated silica to the fused silica (precipitated silica/fused silica) contained in the oral composition is 2.5-11:1.
 5. The oral composition according to claim 1 for the use in the removal of stains attached to the teeth.
 6. The oral composition according to claim 1, wherein the fused silica is fused silica in which particles having a particle size greater than 60 μm are removed by using a sizing device.
 7. The oral composition according to claim 1, wherein the fused silica is fused silica sieved through a 60-μm mesh.
 8. The oral composition according to claim 1, wherein the RDA value is 90 to
 140. 9. The oral composition according to claim 1, wherein the first fused silica having an average particle size of 0.1 to 10 μm accounts for 10 to 90% of the total mass of the fused silica.
 10. The oral composition according to claim 1, wherein the mass ratio of the precipitated silica to the fused silica (precipitated silica/fused silica) contained in the oral composition is from 3:1 to 8:1.
 11. An oral composition comprising: fused silica in an amount of 0.25 to 8.5% by mass; and precipitated silica in an amount of 5 to 26% by mass, wherein the fused silica is a mixture of a first fused silica having an average particle size of 0.1 to 10 μm and a second fused silica having an average particle size greater than 10 μm and equal to or less than 45 μm. 